#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h> 
#include <math.h> 
int main()
{
	double i, s, item;
	i = 1, s = 1;
	while (fabs(1.0 / (i * (i + 2))) > 1.0e-6)
	{
		item = 1 + 1.0 / (i * (i + 2));
		s = s * item;
		i += 2;
	}
	printf("%lf\n", s);
	return 0;
}